column, handrail, blank, space
欄 centers on a bounded section or barrier: a column in a table or text, a handrail that marks an edge, or a blank space to be filled. The meanings share the idea of a defined area or frame.
欄 combines 木 (wood) with 闌, which likely contributes the sound and the idea of a barrier or railing. The original sense is a wooden handrail or fence, later extended to columns and blank spaces.
The left side is wood 木, and the right side 闌 looks like a gate or barrier. Picture a wooden handrail marking off a column of space, like a railing along a balcony or a blank form waiting to be filled.
For ラン, imagine running your hand along a wooden handrail: run -> ラン, and the railing guides you along the column.
section (e.g. in a newspaper); column; page
blank column; blank space
railing; guard rail; handrail; banister; balustrade; parapet
margin
transom
comments section; comment field
comments section (on a blog, website, application, etc.); comment field
TV listings (e.g. in newspaper); TV guide; TV schedules
television listings
TV and radio listings (in a newspaper, etc.)
radio listings
reply section (e.g. on Twitter)
classified ads
top or preceding horizontal column
text at the foot of a page, document, screen, etc.
space without columns
column B (e.g., in a form); second column
personal column
personal-question column
advice column; agony aunt column